Antenna



FIG. 1 is a top plan view of an antenna;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top perspective view thereof; and,

FIG. 5 is a bottom perspective view thereof.

The broken lines are for illustration purposes only and form no part of the claimed invention. 

CLAIM The ornamental design for an antenna, as shown and described. 